Variable delivery vane oil pump, in particular for oil

ABSTRACT

A variable delivery vane pump, in particular for oil, is provided with a stator ( 10 ) eccentrically mounted about a rotor ( 9 ), which is adapted to turn about one own longitudinal axis ( 6 ), and presents a plurality of outwardly radially open grooves ( 15 ) and slidingly engaged, each, by a respective vane ( 17 ) defined by at least two foils ( 25 ) reciprocally overlapped and slidingly coupled one to the other.

TECHNICAL FIELD

The present invention relates to a variable delivery vane pump, in particular for oil.

In particular, the present invention relates to a variable delivery vane pump of the type comprising a rotor, which is mounted to turn about its longitudinal axis, and presents a plurality of outwardly radially open grooves; a stator, which extends around the rotor, and is eccentrically mounted with respect to the rotor itself; a plurality of vanes, each of which is slidingly mounted inside a respective groove, and presents an outer edge facing the stator; and adjusting means for selectively controlling the eccentricity between the rotor and the stator and, therefore, the delivery of the pump.

BACKGROUND ART

The known variable delivery vane pumps of the type described above present some drawbacks mainly deriving from the fact that the efficiency of the fluidtight coupling between the vanes and the stator is relatively reduced and decreases rapidly with pump use.

DISCLOSURE OF INVENTION

It is the object of the present invention to provide a variable delivery vane pump, in particular for oil, which is free from the aforementioned drawbacks.

According to the present invention, there is provided a variable delivery vane pump, in particular for oil, as claimed in the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the accompanying drawings illustrating a non-limitative embodiment example thereof, in which:

FIG. 1 is a schematic longitudinal section of a preferred embodiment of the vane pump of this invention;

FIG. 2 is a section taken along line II-II in FIG. 1;

FIG. 3 is a section taken along line III-III in FIG. 1; and

FIGS. 4 and 5 are two lateral views of two variations of a detail in figures from 1 to 3.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to figures from 1 to 3, it is indicated by 1, as a whole, a variable delivery vane pump, in particular for feeding oil to a lubrication circuit (not shown) of an internal combustion engine (not shown) of a vehicle (not shown).

The pump 1 comprises a supporting case 2, which has an essentially parallelepiped shape with an essentially rectangular section, and comprises, in turn, a first plate 3 laterally limited by an essentially flat surface 4. The plate 3 is provided with a cavity 5, which presents a longitudinal axis 6 orthogonal to the surface 4, outwardly opens at the surface 4, and is axially closed by a second plate 7 arranged in contact with the surface 4 itself.

The pump 1 also comprises a power shaft 8, which is mounted through the plates 3 and 7 to turn about the axis 6, and carries a keyed cylindrical rotor 9, which is housed inside the cavity 5, and presents a width, parallelly measured to the axis 6, essentially equal to the width of the cavity 5, also parallelly measured to the axis 6.

The cavity 5 further houses inside a stator 10, which extends about the rotor 9, presents a width, parallelly measured to the axis 6, essentially equal to the width of the cavity 5 also parallelly measured to the axis 6, and is internally limited by an essentially cylindrical surface 11 arranged in eccentric position with respect to the rotor 9.

The stator 10 is hinged to the plate 3 to oscillate, with respect to the plate 3 itself and under the control of an adjusting device 12 of the known type, about a fulcrum axis 13 parallel to the axis 6 and, therefore, allowing to selectively control the eccentricity between the rotor 9 and the surface 11.

The rotor 9 presents two cylindrical reciprocally opposite cavities 14, which are obtained coaxially to the axis 6, and one facing the plate 3 and the other the plate 7, and is provided with a plurality of radial grooves 15 (in the case shown, six grooves 15), which are obtained through the rotor 9 parallel to the axis 6, are uniformly distributed about the axis 6, radially open outwardly at an outer surface 16 of the rotor 9 coaxially to the axis 6, and further axially open outwardly at the cavities 14.

Each groove 15 is slidingly engaged by a vane 17 presenting an outer edge 18, which extends parallel to the axis 6, and is arranged essentially in contact with the surface 11 of the stator 10 by arranging an annular shoe 19 in between.

The shoe 19 presents a width, parallelly measured to the axis 6, essentially equal to the width of a vane 17 also parallelly measured to the axis 6, and is circumferentially slidable both to the stator 10, and to the vanes 17.

Each vane 17 axially projects from the respective groove 15 inside the cavities 14, and presents an inner edge 20, which extends parallel to the axis 6, and is essentially arranged in contact with two annular elements 21, each of which is accommodated inside one of the cavities 14, extends about the shaft 8, and presents a diameter larger than the diameter of the shaft 8 and smaller than the diameter of the respective cavity 14 so as to float inside the respective cavity 14 itself.

Each pair of respectively adjacent vanes 17 circumferentially defines a respective pumping chamber 22, which is further limited radially by the rotor 9 and by the shoe 19 and axially by the plates 3 and 7, is shifted by the rotor 9 about the axis 6 and through a suction inlet 23 and a delivery outlet 24 of the oil, and presents, following the rotation of the rotor 9 about the axis 6 and the eccentricity between the rotor 9 and the surface 11 of the stator 10, a variable volume.

Furthermore, with regard to this it is important to point out that the volume of each chamber 22 at the inlet 23 and at the outlet 24 and, therefore, the delivery of the pump 1 are selectively controlled by shifting the stator 10 about the axis 13 and, therefore, modifying the eccentricity between the rotor 9 and the surface 11 of the stator 10 itself.

As shown in FIG. 2, each vane 17 comprises a plurality of foils 25 (in the case shown, four foils 25), which are reciprocally overlapped, and are slidingly radially coupled one to the other to ensure a relatively efficient fluidtight coupling between the vane 17 and the shoe 19.

With reference to FIG. 4, the annular shoe 19 is replaced with a plurality of shoes 26 (in the case shown, three shoes 26), each of which is arranged between the surface 11 and two respective vanes 17, is slidingly circumferentially coupled to the surface 11 and to the respective vanes 17, and presents two curved ends 27, one of which is essentially arranged in contact with a respective vane 17.

With reference to FIG. 5, the annular shoe 19 is replaced with a single shoe 28, which is arranged between the surface 11 and the vanes 17, extends about the axis 6 according to an angle smaller than 360°, is slidingly circumferentially coupled to the surface 11 and to the vanes 17, and presents two curved ends 29, one of which is essentially arranged in contact with a respective vane 17.

According to a variation not shown, the shoes 19, 26, and 28 are housed inside respective cavities, which are obtained in the stator 10, and outwardly open at the surface 11, and outwardly project from the respective cavities to arrange themselves in contact with the respective vanes 17.

According to a further variation not shown, the curved ends 27, 29 of each shoe 26, 28 are replaced with two enlarged edges parallel to the axis 6.

The operation of the pump 1 is easily inferred from the description set forth above and does not require further explanations. 

1. A variable delivery vane pump, the pump comprising: a rotor said rotor being mounted to turn about a longitudinal axis said rotor presenting a plurality of grooves outwardly radially open at a surface essentially coaxial to said axis; a stator said stator extending about the rotor, and being eccentrically mounted with respect to the rotor; a plurality of vanes, each of said vanes being slidingly mounted inside a respective one of said groove, and presenting an outer edge facing the stator; an adjustor said adjustor selectively controlling an eccentricity between the rotor and the stator; each of said vane comprising at least two foils said foils being reciprocally overlapped and slidingly coupled one to the other.
 2. A pump according to claim 1 further comprising two annular elements said annular elements being arranged on opposite bands of the rotor parallel to said axis, and extending about the axis; each of said vane axially projecting from one of said respective groove and presenting an inner edge disposed to contact said annular elements.
 3. A pump according to claim 1 further comprising a sliding element arranged between the stator and an outer edges of at least one of the vanes.
 4. A pump according to claim 3 further comprising a single one of said sliding element extending about said axis substantially about 360°.
 5. A pump according to claim 3 further comprising a single one of said sliding element extending about said axis according to an angle smaller than 360°.
 6. A pump according to claim 5, further comprising said sliding element presenting two curved ends.
 7. A pump according to claim 5, further comprising said sliding element presenting two enlarged end edges substantially parallel to said axis.
 8. A pump according to claim 3 further comprising at least two of said sliding elements distributed about said axis.
 9. A pump according to claim 8, further comprising each of said sliding elements presenting two curved ends.
 10. A pump according to claim 8, further comprising each of said sliding elements presenting two enlarged end edges substantially parallel to said axis.
 11. A pump according to claim 3 further comprising each of said sliding elements being slidingly circumferentially coupled to the stator and to the vanes.
 12. A variable delivery vane pump, the pump comprising: a rotor said motor being mounted to turn about a longitudinal axis, and presenting a plurality of grooves outwardly open at surface essentially coaxial to said axis; a stator, said stator extending about the rotor, and being eccentrically mounted with respect to the rotor; a plurality of vanes, each of said vanes being slidingly mounted inside a respective one of said groove, and presenting an outer edge facing the stator; an adjustor selectively controlling an eccentricity between the rotor and the stator each vane comprising at least two foils reciprocally overlapped and slidingly coupled one to the other; and at least one sliding element being arranged between the stator and the vanes. 